Quick change toolpost for my Portass PD5

Does anyone know whether the wedge gib type cuneiform quick change toolpost 250-000 will work well on my Portass PD5 (3.5 inch swing) lathe?  What will be the pros and cons of this? Is it too big? Can you recommend anything better?

Thank you - Rowan

Edited By JasonB on 14/11/2022 16:39:46

Only you can do the maths. You need to measure the distance of the top surface of the topslide to the centre of the spindle. Then find a drawing of the intended holders and work out if a sensible sized, ie 1/4 in not 12mm HSS toolbit can fit and not be above centre height.

Since you need lots of toolholders in the end even cheap ones mount up and end up costing more than the lathe. So ask yourself the question ' are you in such a despearate hurry to change tools all the time that a QCTP is more valuable to you than buying the material to make a tailstock die holder, fixed steady, etc.

Rowan,

Be careful before you order a toolpost from the site to which you linked. My reading of the ad is that you pay about £50 for just the toolpost plus nearly £29 for postage. No toolholders included. I would suggest you shop at ArcEoroTrade and pay a little more for a toolpost and three holders and treat yourself to more for Christmas.

Well, that's what I'd do, having selected the correct size toolpost as Bayzle has said. If it's of any help, I have that size fitted to my lathe and it's an Asian 9x20 clone, identical to an Axminster BL20.

John

A 250 size toolpost will probably be too big for 3.5" swing. I have a 250 on my Boxford 4.5" swing and it just fits.

regards

Thank you for those answers. In trying to understand whether this will fit, I need to understand the function of the piece of metal ringed in red here:

What is the function of this? Can I remove it? Will the toolpost still work? Or can I make a smaller version of it, that will allow tool holders to be slid down so that they extend below the dovetail on the toolpost?

Thank you - Rowan

What exactly is the problem if the tool post is too big for the lathe? What fouls with what?

Can one buy toolposts of this type smaller than the 250 size? From whom?

Thank you - Rowan

That part circled in red (your photo) can be removed and machined as you need. In my case I milled it to fit a slot in a compound slide.

It is a bit confusing, but the numbering of the various sizes of this series of toolposts all start 250-. The 250-0xx is the smallest, the next is 250-1xx or AXA, then 250-2xx or BXA etc. The dimensions of the 250-000 toolpost can be found on the Arceurotrade website which also indicates suitability for mini lathes.

Do ensure you get a wedge design rather than piston type because the positioning of the cutting edge is much more consistent when removed and replaced. An advantage of the 250- design is that it is fairly simple to make your own toolholders.

Buying from a UK vendor usually means that someone has vetted the supplier to provide reasonable quality.

Edited By Macolm on 14/11/2022 21:14:17

Edited By Macolm on 14/11/2022 21:17:07

Edited By Macolm on 14/11/2022 21:17:31

Rowan, I notice in a much earlier post relating to parting tools you mention that the spindle centre is only 8mm above the top of the compound slide ?

" On my lathe (a Portass PD5) the surface of the compound slide that tools are clamped to is about 8mm below the centre height. This seems to mean that I can't use a tool thicker than 8mm (or more precisely, whose cutting edge is more than 8mm above its base). So how can I use a tool like this: "

This dimension seems very small and looking at lathes.co.uk it appears that the difference is considerably greater than 8mm ?

Looking on Arc's site the smallest tool post needs a minimum of H + h = 20mm allowing for say a 10mm tool bit you need 17.5mm minimum.

If the above 8mm is correct then there are alternatives you could consider, the easiest being the Gibraltar style tool post where the compound slide is removed and a solid block of appropriate thickness fitted and the QC tool post mounted on this.

Hope this helps

John